Technology

SkyTruth uses remote sensing and digital mapping to inform the public, scientific research, and policy-makers about the impacts of human activity on the environment.

(In green) The approximate path of the Dona Liberta, a ship we concluded was responsible for a 95 mile-long bilge dump off the coast of Angola in 2012. We used a combination of radar satellite imagery and ship-location data to identify this polluting vessel and demonstrate the potential of remote sensing to monitor illegal and environmentally damaging activity at sea. Read more about the Dona Liberta on our blog.

Remote Sensing: This technical term is broadly defined as studying a subject (in our case, the Earth) without being in physical contact with it. At SkyTruth, we specialize in analyzing images captured by satellites and aircraft, and processing data picked up by satellite-borne sensors. Imagery provides a unique perspective on environmental issues, allowing us to display to the world what you cannot perceive from the ground. Satellites have global coverage, which allows us to easily observe both oil spills in the Gulf of Mexico and a colossal gold mine in Indonesia, without ever leaving home. Aerial photography gives us a bird’s-eye view of giantmines and backyard fracking, with detail much greater than publicly available satellite imagery. Other remote sensing data we use include the location of ships at sea and fires detected by orbiting satellites.

Digital Mapping: Not all data picked up by satellites or produced by people on the ground is easy to understand, so we use geographic information systems (GIS) to interpret and map information relevant to our mission. For example, the U.S. Coast Guard annually receives around 30,000 pollution reports through the National Response Center (NRC). Few people have the time or patience to sort through thousands of text-only reports, so we devised a tool to collect all of these reports, pull out the important information, and plot it all on a map for anyone to access. We turned this map into our SkyTruth Alerts tool, a free subscription that notifies users by email whenever pollution is reported in their subscription area. We are adding drilling-related reports for states we can find reliable data for, and we are always looking for new ways to keep you informed what is happening in the places you care about.

From fires to fracking reports, we are always looking for new ways to make important data useful and accesibile to the public. Check out our blog to see all of the ways we use digital mapping to study the environment.

Satellites: When it comes to remote sensing, the hardware tends to steal the show. So here is more detail about the instruments we use. (Above: Artist rendering of Landsat 8 superimposed over the Gulf of Mexico. Image courtesy of NASA)

In 1972 NASA launched a modified weather satellite, now known as Landsat 1, to study the Earth and humanity’s impact on it. In the 1980s and 90s, the Landsat program was privatized and a single image cost $4,400. Only corporations with deep pockets could afford to routinely analyze the Earth on satellite images, and they did so to identify new places to drill for oil or mine for gold. The inspiration for SkyTruth came from the realization that the same tools were also powerful witnesses to the impact of resource exploration and extraction.

Four decades after the launch of Landsat 1, technology has improved and so has access to the data. Landsat 7 and 8 orbit the planet collecting visible and infrared images of the earth’s surface, adding to 3.8 million other Landsat satellite images available to the public to download – for free. MODIS satellites Terra and Aqua collect low-resolution images of every spot on the planet, two time a day. The Suomi National Polar-orbiting Partnership satellite orbits the earth 14 times per day detecting nighttime lights and fires and constellations ofSynthetic Aperture Radar (SAR) satellites penetrate cloud cover to detect ships and oil slicks – day or night.

For more information about the technology we use, follow our blog for the latest updates.

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